I'm going to brew up some double IPA next weekend which should come out to around 9.5% ABV. Will WLP001 be able to handle this? I have some in the fridge and would like to use it, but only if it will live. I could save it for another batch later.

As an alternative I was thinking of trying WLP090 San Diego Super Yeast which has a higher alcohol tolerance.

The 001 should do just fine as long as you pitch enough cells. Since you already have it, I say use it. 090 is a great yeast, too, but honestly the 001 won't have any trouble at all fermenting to 9.5%.

Wlp001 is pretty much the same as us-05 and an HBT member recently told me he has used 05 in beers between 8-11% ABV without difficulty. Should be fine but make sure you have plenty of soldiers to win the invasion! Lol